The organization of inputs to the lateral geniculate nucleus (LGN) is studied. The number and type of inhibitory retinal inputs impinging--via interneurons--onto individual relay cells will be characterized. The data will be classified by relay cell type and by ganglion cell input type. Computer based cross-correlation techniques are combined with dual microelectrode recording in the retina and in the LGN. Supperconductivity phenomena in individual ganglion cell axons will be studied. Aspects of ganglion cell receptive field organization will be studied both by the use of current injection into horizontal cells and by pharmacological studies involving adrenergic transmitters. All of the above work uses the cat as the experimental animal in a long-term acute preparation. Comparative anatomical studies of vertebrate retinas are also carried out.